There could be a tweak here for clarity. The top-left Pop-up toggles between "Replace Existing Records" and "Append to Existing Records" The Pop-up below that toggles between "Append Fields in Order" and "Append Fields by Name" regardless of the top selection. It would make more sense if the lower choices offered Append… or Replace… options based on the top selection. As the dialog appears to be constructed from PanX I presume this change is possible and relatively simple.
Hmm, I think a better change would be to make the options:
I don't think either Append (the current text) or Replace makes sense.
I agree, better.